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James Carney
Full Member
Registered: 07/30/10
Posts: 440
Loc: new york city

Next month I am going to install WNG parts in a Sohmer grand that I acquired earlier this year. This will be my first time working with these parts, and I am very excited about it. I won't be replacing the back action, just reps, shanks, and flanges. I will probably replace the capstans with WNG anodized as well.

For those of you that have experience, are there any tips you can share to make the installation go as smoothly as possible? Are there any special tools I will need? I did some PW searches and read that some shank flanges might need repinning, but not nearly as many as on a typical wooden set. I'm also curious if the WNG wips typically need any repinning, especially the rep lever. Is it also true that the ideal pinning in grams for WNG parts is different from wood?

And, lastly, is it generally a good idea to remove the hammer rest rail and go with individual hammer rests?

A tech friend has the complete sample set of WNG wippens so I'm confident I will be able to choose and order the best setup for this particular piano, but advice on making these choices is most welcome.

For those of you that have experience, are there any tips you can share to make the installation go as smoothly as possible? Are there any special tools I will need? I did some PW searches and read that some shank flanges might need repinning, but not nearly as many as on a typical wooden set. I'm also curious if the WNG wips typically need any repinning, especially the rep lever. Is it also true that the ideal pinning in grams for WNG parts is different from wood?

Hi Jim,

On my last set of whips I ended up repinning all the whip flanges which were @ 4-7g. So you should get the WNG repinning tool,a set of pins and their broaches. These pins are graded in tiny, tiny increments, and are not the same sizes as standard pins, so you need the pins and broaches as well if you are going to repin. As well the repinning kit comes with hard bushing retainer, to keep the hard bushing from poppong out when reaming.

All this might seem a little foreboding, but like standard pinning, once you go through a set, you get the hang of it. Its not hard, just different. You don't cut like reaming felt, but you compress the bushing.

Originally Posted By: James Carney

And, lastly, is it generally a good idea to remove the hammer rest rail and go with individual hammer rests?

Probably not a good idea to remove the hammer rest rail. Many pianos require the hammers to be swung a bit to align with the strings. Bruce call this "Cross Striking". The hammer rest rail allows you accommodate the alignment as necessary without going off the side of the individual hammer rest felt. Also, I find it much easier to get the required shank to rest felt clearance @ rest when the hammer rest is moveable. It is a bit noisier....choose your poison...

Originally Posted By: James Carney

A tech friend has the complete sample set of WNG wippens so I'm confident I will be able to choose and order the best setup for this particular piano, but advice on making these choices is most welcome.

The sample set is essential. Since the whips and shanks heels, knuckles, are modular, you can configure the parts to your advantage. By setting up the samples as you want them before ordering you can take advantage of the design flexibility, as opposed to locking yourself into standard dimensions...which may or may not make sense in this piano.

If you are going to apply the heels and /or knuckles yourself (easy) get 2 tubes of glue...1 for the hammers and extra for other parts.

As far as gluing on the shanks, practice before hand. You have to get the hammer on and positioned quickly. I did come up with a glue application technique for the shank/hammer joint which I greatly prefer to what WNG taught.

Leave the glue in the tube, and as you work on each individual hammer, squeeze out a small 1" long ( or so)line of glue on the shank...just a single not too heavy line of glue. Then take a hobby store 1/4" ID piece of hollow aluminum tubing (these have very thin walls for hobby work)and cut/sand/whatever 1/2 the circumference off for about 1" at the end of the tube. Take the now exposed inside radius of the tube, place it on the end of the shank on the previously applied glue line and twist the tubing around the shank to spread the glue evenly around the shank. I think this works great and fast. The CA glue does not harden on the spreading tube, interestingly. If it does get globbed up a bit, it wipes easily with a paper towel.

James Carney
Full Member
Registered: 07/30/10
Posts: 440
Loc: new york city

Jim! I was hoping you would respond; thanks for all of this great information.

Another puzzle that you may be able to help solve...

The WNG technician site states that as long as the repetition flange center to jack flange center is 99mm (+ or - 1mm) everything is good to go as-is. Well, my rep to jack centers on this Sohmer are 97.5mm. The site mentions that it is still possible to use WNG reps if the distance isn't in that zone but that it's no longer a simple matter of just screwing the new parts to the rails. However, there is no mention of what needs to be done to make it work. Any experience here with reps that are "out of the zone?"

Some additional info that I just gathered...

Sohmer Model 41 cupid grand (1933)Action ratio is high - around 6.1Action spread is 113.5The original reps use a low angle jack that appears to match up well with the WNG low angle jack. It also looks like I will have to modify the wippen rail with a clearance cut, no big deal.

I will likely want to relocate capstans so I'll go with WNG anodized. Looks like there is also a substantial amount of lead in the keys, some of which can likely be eliminated.

Will be using Ronsen Weickerts and restringing with an updated scale...

... If you are going to apply the heels and /or knuckles yourself (easy) get 2 tubes of glue...1 for the hammers and extra for other parts.

As far as gluing on the shanks, practice before hand. You have to get the hammer on and positioned qui ckly. I did come up with a glue application technique for the shank/hammer joint which I greatly prefer to what WNG taught.

Leave the glue in the tube, and as you work on each individual hammer, squeeze out a small 1" long ( or so)line of glue on the shank...just a single not too heavy line of glue. Then take a hobby store 1/4" ID piece of hollow aluminum tubing (these have very thin walls for hobby work)and cut/sand/whatever 1/2 the circumference off for about 1" at the end of the tube. Take the now exposed inside radius of the tube, place it on the end of the shank on the previously applied glue line and twist the tubing around the shank to spread the glue evenly around the shank. I think this works great and fast. The CA glue does not harden on the spreading tube, interestingly. If it does get globbed up a bit, it wipes easily with a paper towel.

That would solve the problem I've had gluing hammers to these things. Gluing on the hammers has been one of the main difficulties with cf hammershanks.

Ed McMorrow described another technique a while back. Simply dry-fit all of the hammers on the new shanks, line them up where you want them and put a few drops of thin CA glue at each joint. Capillary action will draw the CA glue in and the hammers are glued permanently in place. I haven't tried this myself but it does sound like a good idea.

... If you are going to apply the heels and /or knuckles yourself (easy) get 2 tubes of glue...1 for the hammers and extra for other parts.

As far as gluing on the shanks, practice before hand. You have to get the hammer on and positioned qui ckly. I did come up with a glue application technique for the shank/hammer joint which I greatly prefer to what WNG taught.

Leave the glue in the tube, and as you work on each individual hammer, squeeze out a small 1" long ( or so)line of glue on the shank...just a single not too heavy line of glue. Then take a hobby store 1/4" ID piece of hollow aluminum tubing (these have very thin walls for hobby work)and cut/sand/whatever 1/2 the circumference off for about 1" at the end of the tube. Take the now exposed inside radius of the tube, place it on the end of the shank on the previously applied glue line and twist the tubing around the shank to spread the glue evenly around the shank. I think this works great and fast. The CA glue does not harden on the spreading tube, interestingly. If it does get globbed up a bit, it wipes easily with a paper towel.

That would solve the problem I've had gluing hammers to these things. Gluing on the hammers has been one of the main difficulties with cf hammershanks.

Ed McMorrow described another technique a while back. Simply dry-fit all of the hammers on the new shanks, line them up where you want them and put a few drops of thin CA glue at each joint. Capillary action will draw the CA glue in and the hammers are glued permanently in place. I haven't tried this myself but it does sound like a good idea.

ddf

The procedure I have developed is to put a bit of the gel CA on the shank just outboard from the hammer location. Then I put a thick liquid CA in the hammer hole. Put the hammer on the shank, rotate once as it's going on and adjust to final position.

Sohmer Model 41 cupid grand (1933)Action ratio is high - around 6.1Action spread is 113.5The original reps use a low angle jack that appears to match up well with the WNG low angle jack. It also looks like I will have to modify the wippen rail with a clearance cut, no big deal.

Since the dimensions lie outside of current standards, or even if they didn't I would suggest starting your action redesign by proving the stack geometry.

In setting up S&S action frames for techs of many different action design skill sets, I have found that there is a fair amount confusion about what the stack geometry is supposed to accomplish. I'm designing a class for next years Boston NEECSO called "Understanding Spread" to address this confusion.

As I see it, and I would love input from Del, Ed Foote, et al regarding the the following, the goal of the stack's geometry is to:

1-arrange for the jack to contact the knuckle at an advantageous angle with key at rest.2-locate the jack in the rep lever window so that there is sufficient room for both escapement and aftertouch without bottoming out on the jack stop felt3-with the jack/knuckle angle at an efficient rest angle, the jack located with sufficient room for escapement/aftertouch, and the action feet sitting elevated on the tapered or non-tapered riser blocks, arrange for the shank, at rest, to be 5mm or so off the rest felt.

As far as overall key&action leverage, within functional limits defined by the given parts, the stack has very little to do directly with defining overall key&action leverage. Leverage is primarily defined by key balance point, capstan location, knuckle distance from shank center, heel distance from whip center and shank length.

So in changing parts, you need to prove that the 3 items above can be accomplished with these new parts, on the existing or modified action frame.

To do this...

Mount a new rep flange and shank flange on the existing stack. Measure the spread. Also with the action frame mounted on the key frame and riser assembly,measure the height differential between the whip center and the shank center.

What you have just measured is, in effect, a radius of a circle(spread is a radius with the shank center the center of the radius), and where on that radius in, relation to horizontal, the whip center lies.

-Take a 1'x1'piece of mdf of other flat smooth sheet stock.

-Set a drafting compass to draw a radius that matches the spread you just measured.

-with a .050 drill bit, drill a hole 1/4" or so deep in the center of the mdf. Set one foot of the compass in that hole(that hole is your shank center location) and draw a spread arc.

-draw a line, call it line#1, through the shank center hole and roughly perpendicular to 2 sides of your 1'x1' square mdf.

-draw a line, call it line #2 parallel to the line you just drew, offset from that line by the differential you measured between shank center and whip center heights. Current standards use 2.5" as this differential, but your Sohmer might well be different.

-you'll notice that line #2 intersects the spread radius at some point. That point is your whip center location. Drill .050" hole at this whip center location.

-Take a proposed shank and whip, with a pin punch push the center out enough so that the center pin can engage the holes you drilled in the mdf. Locate the shank and whip as defined by the drilled holes.

Set the parts so jack touches the knuckle, while the shank is resting 5mm off jack rest felt. (with rest rail, you will have to transfer this felt location from the existing stack. On an integral whip with rest felt, you are all set).

-In this position, a line drawn perpendicular to the shank, through the center of the knuckle spline, should pass to the distal side of the jack center by a 1/8" or so. This line is defining the jack/knuckle contact angle referred to above.

-Also, in this position, where is the jack in the rep lever window in relation to the "score mark"...ie, is there enough room for escapement & aftertouch.

If the parts don't line up with these standards, or somewhere reasonably close to them, draw other spread arcs and differentials until things alighn properly within the stack.

Hope that's not too long and hard to understand. The point is that, rather than recite dimensions to adhere to, understanding what you are trying to achieve gives you more scope to understand the action geometry changes you are trying to make. It will allow you to understand why you should either avoid the changes or make the changes with confidence.

Jim Ialeggio

ps chances are the string height on this Sohmer are outside of the 7 1/4" to 7 1/2" standards. This is more reason to make sure the new parts will be able to be aligned with the various parameters defined by the existing piano.

ps chances are the string height on this Sohmer are outside of the 7 1/4" to 7 1/2" standards. This is more reason to make sure the new parts will be able to be aligned with the various parameters defined by the existing piano.

many grands are using 7 3/4" You do not take in account the jack rotation, and how it relates to the line of spread in your evaluation ?

there is a neat geometrical method I am still translating it.

Edited by Olek (07/28/1304:53 AM)

_________________________
Professional of the profession. Foo Foo specialistI wish to add some kind and sensitive phrase but nothing comes to mind.!

>-In this position, a line drawn perpendicular to the shank, through the center of >the knuckle spline, should pass to the distal side of the jack center by a 1/8" or >so. This line is defining the jack/knuckle contact angle referred to above.

At rest, the line from the knuckle core should align with the jack center pin.

>-In this position, a line drawn perpendicular to the shank, through the center of >the knuckle spline, should pass to the distal side of the jack center by a 1/8" or >so. This line is defining the jack/knuckle contact angle referred to above.

At rest, the line from the knuckle core should align with the jack center pin.

Not always the case, on some stacks that are inclined it is possible, but the center of the knuckle can line with the center of the jack and the back of the core line with the back of the jack) - the longer distance in regard of the knuckle is best indeed, provide more acceleration (distance reduction form +- 21 mm to +-19 mm between the jack and the hammer center)

Of course should not pass the jack center.

How the jack to knuckle is located in regard to the centers line determines the amount of friction during letoff.Indeed hammer bore is there the main element.

open jack angle helps to line the jack contact point on the button, with the line of centers, assuming the hammer bore is good, friction on the button is then at its lower.

Edited by Olek (07/28/1309:17 AM)

_________________________
Professional of the profession. Foo Foo specialistI wish to add some kind and sensitive phrase but nothing comes to mind.!

James Carney
Full Member
Registered: 07/30/10
Posts: 440
Loc: new york city

Originally Posted By: jim ialeggio

Originally Posted By: James Carney

Sohmer Model 41 cupid grand (1933)Action ratio is high - around 6.1Action spread is 113.5The original reps use a low angle jack that appears to match up well with the WNG low angle jack. It also looks like I will have to modify the wippen rail with a clearance cut, no big deal.

Since the dimensions lie outside of current standards, or even if they didn't I would suggest starting your action redesign by proving the stack geometry.

In setting up S&S action frames for techs of many different action design skill sets, I have found that there is a fair amount confusion about what the stack geometry is supposed to accomplish. I'm designing a class for next years Boston NEECSO called "Understanding Spread" to address this confusion.

As I see it, and I would love input from Del, Ed Foote, et al regarding the the following, the goal of the stack's geometry is to:

1-arrange for the jack to contact the knuckle at an advantageous angle with key at rest.2-locate the jack in the rep lever window so that there is sufficient room for both escapement and aftertouch without bottoming out on the jack stop felt3-with the jack/knuckle angle at an efficient rest angle, the jack located with sufficient room for escapement/aftertouch, and the action feet sitting elevated on the tapered or non-tapered riser blocks, arrange for the shank, at rest, to be 5mm or so off the rest felt.

As far as overall key&action leverage, within functional limits defined by the given parts, the stack has very little to do directly with defining overall key&action leverage. Leverage is primarily defined by key balance point, capstan location, knuckle distance from shank center, heel distance from whip center and shank length.

So in changing parts, you need to prove that the 3 items above can be accomplished with these new parts, on the existing or modified action frame.

To do this...

Mount a new rep flange and shank flange on the existing stack. Measure the spread. Also with the action frame mounted on the key frame and riser assembly,measure the height differential between the whip center and the shank center.

What you have just measured is, in effect, a radius of a circle(spread is a radius with the shank center the center of the radius), and where on that radius in, relation to horizontal, the whip center lies.

-Take a 1'x1'piece of mdf of other flat smooth sheet stock.

-Set a drafting compass to draw a radius that matches the spread you just measured.

-with a .050 drill bit, drill a hole 1/4" or so deep in the center of the mdf. Set one foot of the compass in that hole(that hole is your shank center location) and draw a spread arc.

-draw a line, call it line#1, through the shank center hole and roughly perpendicular to 2 sides of your 1'x1' square mdf.

-draw a line, call it line #2 parallel to the line you just drew, offset from that line by the differential you measured between shank center and whip center heights. Current standards use 2.5" as this differential, but your Sohmer might well be different.

-you'll notice that line #2 intersects the spread radius at some point. That point is your whip center location. Drill .050" hole at this whip center location.

-Take a proposed shank and whip, with a pin punch push the center out enough so that the center pin can engage the holes you drilled in the mdf. Locate the shank and whip as defined by the drilled holes.

Set the parts so jack touches the knuckle, while the shank is resting 5mm off jack rest felt. (with rest rail, you will have to transfer this felt location from the existing stack. On an integral whip with rest felt, you are all set).

-In this position, a line drawn perpendicular to the shank, through the center of the knuckle spline, should pass to the distal side of the jack center by a 1/8" or so. This line is defining the jack/knuckle contact angle referred to above.

-Also, in this position, where is the jack in the rep lever window in relation to the "score mark"...ie, is there enough room for escapement & aftertouch.

If the parts don't line up with these standards, or somewhere reasonably close to them, draw other spread arcs and differentials until things alighn properly within the stack.

Hope that's not too long and hard to understand. The point is that, rather than recite dimensions to adhere to, understanding what you are trying to achieve gives you more scope to understand the action geometry changes you are trying to make. It will allow you to understand why you should either avoid the changes or make the changes with confidence.

Jim Ialeggio

ps chances are the string height on this Sohmer are outside of the 7 1/4" to 7 1/2" standards. This is more reason to make sure the new parts will be able to be aligned with the various parameters defined by the existing piano.

Sohmer Model 41 cupid grand (1933)Action ratio is high - around 6.1Action spread is 113.5The original reps use a low angle jack that appears to match up well with the WNG low angle jack. It also looks like I will have to modify the wippen rail with a clearance cut, no big deal.

Since the dimensions lie outside of current standards, or even if they didn't I would suggest starting your action redesign by proving the stack geometry.

In setting up S&S action frames for techs of many different action design skill sets, I have found that there is a fair amount confusion about what the stack geometry is supposed to accomplish. I'm designing a class for next years Boston NEECSO called "Understanding Spread" to address this confusion.

As I see it, and I would love input from Del, Ed Foote, et al regarding the the following, the goal of the stack's geometry is to:

1-arrange for the jack to contact the knuckle at an advantageous angle with key at rest.2-locate the jack in the rep lever window so that there is sufficient room for both escapement and aftertouch without bottoming out on the jack stop felt3-with the jack/knuckle angle at an efficient rest angle, the jack located with sufficient room for escapement/aftertouch, and the action feet sitting elevated on the tapered or non-tapered riser blocks, arrange for the shank, at rest, to be 5mm or so off the rest felt.

As far as overall key&action leverage, within functional limits defined by the given parts, the stack has very little to do directly with defining overall key&action leverage. Leverage is primarily defined by key balance point, capstan location, knuckle distance from shank center, heel distance from whip center and shank length.

So in changing parts, you need to prove that the 3 items above can be accomplished with these new parts, on the existing or modified action frame.

To do this...

Mount a new rep flange and shank flange on the existing stack. Measure the spread. Also with the action frame mounted on the key frame and riser assembly,measure the height differential between the whip center and the shank center.

What you have just measured is, in effect, a radius of a circle(spread is a radius with the shank center the center of the radius), and where on that radius in, relation to horizontal, the whip center lies.

-Take a 1'x1'piece of mdf of other flat smooth sheet stock.

-Set a drafting compass to draw a radius that matches the spread you just measured.

-with a .050 drill bit, drill a hole 1/4" or so deep in the center of the mdf. Set one foot of the compass in that hole(that hole is your shank center location) and draw a spread arc.

-draw a line, call it line#1, through the shank center hole and roughly perpendicular to 2 sides of your 1'x1' square mdf.

-draw a line, call it line #2 parallel to the line you just drew, offset from that line by the differential you measured between shank center and whip center heights. Current standards use 2.5" as this differential, but your Sohmer might well be different.

-you'll notice that line #2 intersects the spread radius at some point. That point is your whip center location. Drill .050" hole at this whip center location.

-Take a proposed shank and whip, with a pin punch push the center out enough so that the center pin can engage the holes you drilled in the mdf. Locate the shank and whip as defined by the drilled holes.

Set the parts so jack touches the knuckle, while the shank is resting 5mm off jack rest felt. (with rest rail, you will have to transfer this felt location from the existing stack. On an integral whip with rest felt, you are all set).

-In this position, a line drawn perpendicular to the shank, through the center of the knuckle spline, should pass to the distal side of the jack center by a 1/8" or so. This line is defining the jack/knuckle contact angle referred to above.

-Also, in this position, where is the jack in the rep lever window in relation to the "score mark"...ie, is there enough room for escapement & aftertouch.

If the parts don't line up with these standards, or somewhere reasonably close to them, draw other spread arcs and differentials until things alighn properly within the stack.

Hope that's not too long and hard to understand. The point is that, rather than recite dimensions to adhere to, understanding what you are trying to achieve gives you more scope to understand the action geometry changes you are trying to make. It will allow you to understand why you should either avoid the changes or make the changes with confidence.

Jim Ialeggio

ps chances are the string height on this Sohmer are outside of the 7 1/4" to 7 1/2" standards. This is more reason to make sure the new parts will be able to be aligned with the various parameters defined by the existing piano.

I see parts of the method I translate, but is not the horizontal placement of the whippen lever necessary ? (at half blow for uprights)It is somewhat similar, but use a projection of both whippen and jack axis as circles radius, that help to locate the horizontal position for the whippen.

At rest, the line from the knuckle core should align with the jack center pin.

Jon,

my take on this is that in theory, as you say, the line drawn perpendicular to the shank, through the center of the knuckle core should go through the jack center.

My suggestion for the line to be favoring the distal side of the jack center is to allow for inevitable wear. Wear, as I see it, will swing that line proximally. If the line starts, with new parts, at the jack center, wear will drive the line to the proximal side of the center, making the jack work at a mechanical disadvantage. Starting out slightly distal to the jack center will keep the jack at an advantageous angle for a longer period of time.

At rest, the line from the knuckle core should align with the jack center pin.

Jon,my take on this is that in theory, as you say, the line drawn perpendicular to the shank, through the center of the knuckle core should go through the jack center. My suggestion for the line to be favoring the distal side of the jack center is to allow for inevitable wear. Wear, as I see it, will swing that line proximally. If the line starts, with new parts, at the jack center, wear will drive the line to the proximal side of the center, making the jack work at a mechanical disadvantage. Starting out slightly distal to the jack center will keep the jack at an advantageous angle for a longer period of time. ..no???...Jim Ialeggio

Greetings, If the line perpendicular to the shank, through the knuckle, crosses the centerpin of the jack, at rest, (and I am speaking of the centerline of the knuckle core to the center of the pin), the geometry is at its most efficient for transferring energy, in that there is the least amount of force vectored away from the knuckles movement around the shank center pin. From that point on, the distal arc of the jack's tip,(around the whippen center), combined with the opposing arc of the knuckle, around the shank's center, would ideally be congruent enough to keep the relative motion between them at zero, removing sliding friction. I think R. Overs is on top of that as a design principle. What I find, in practice, is that getting the alignment so that the perpendicular line begins by being very slightly proximal to the jack's pin allows a longer "dwell time" in the ideal zone, rather than leaving it at the starting point.

The major influence in this arrangement seems to be the size of the knuckle, not the hammer blow distance. I also don't know how much effect it has. Long ago, I changed knuckle sizes on some of the small teflon actions to good effect, (back when it made sense to with the existing parts). The WNG parts make this a simple tuning chore when building an action, too. Regards,

What I find, in practice, is that getting the alignment so that the perpendicular line begins by being very slightly proximal to the jack's pin allows a longer "dwell time" in the ideal zone, rather than leaving it at the starting point.

Ed,

Did you mean to say "proximal"? When the perpendicular starts proximal to the jack center, the pianist is required to supply more force at the beginning of the stroke to get things moving. Then, as the perpendicular passes through and to the well to the distal side of the pin, the required force markedly decreases...though in truth I think the pianist-perceptible effects of this fine point may be academic.

The best "bang-for-the-buck", in terms of changing the way the pianist experiences letoff, is knuckle size. It trumps all the micro effects...at least in my opinion.

I like the 9mm knuckle, and its what M&H is using on their actions.

As another way to mess with the relative feeling of letoff, I have been experimenting with setting the distal side of the jack jack closer to the knuckle spline center at rest. This reduces the amount of resistance felt at letoff as well. I'm finding that the jack can be advanced a bit and still be a safe distance from "cheating",though I'm still trying to decide what I think of this adjustment.

Jim...the bottom line in terms of your question is that the range of functionality is pretty large,relatively speaking. By setting things up in a way that you can see the geometry,you get a good visual understanding of how the parts line up, and also gives you a tool to know when the parts are set up outside of functionality.

Greetings, If the line perpendicular to the shank, through the knuckle, crosses the centerpin of the jack, at rest, (and I am speaking of the centerline of the knuckle core to the center of the pin), the geometry is at its most efficient for transferring energy, in that there is the least amount of force vectored away from the knuckles movement around the shank center pin. From that point on, the distal arc of the jack's tip,(around the whippen center), combined with the opposing arc of the knuckle, around the shank's center, would ideally be congruent enough to keep the relative motion between them at zero, removing sliding friction. I think R. Overs is on top of that as a design principle. What I find, in practice, is that getting the alignment so that the perpendicular line begins by being very slightly proximal to the jack's pin allows a longer "dwell time" in the ideal zRegards,

Yes, no sliding friction at the knuckle/jack interface would be ideal, but it's not the reality. I studied this effect quite closely using a Solidworks model of an action, and there's plenty of sliding. It is for this reason that people have experimented with rotating knuckles, and it is for this reason that Ron Overs changed the geometry of his action. I believe Ron's changes are both warranted and technically sound.

Yes, no sliding friction at the knuckle/jack interface would be ideal,

Not sure I agree with this. The added resistance at letoff gives the pianist critical information of when to "go for it". I have experimented with eliminating that perception of resistance at letoff, by both raising drop very very high and advancing the jack into the cheat zone. In both instances it became very difficult, from a pianistic stand point to gauge where I was in the keystroke and how much pressure I should apply to get the tone I wanted.

Steingraber experimented with and produced a rolling knuckle for a little while. Udo pulled it entirely because pianists hated it.

I believe we may have some form of compression of the action, more or less pronounced depending of the position of the jack, Then the position of jack and knuckle in regard of the spread line at letoff moment , and the amount of friction on the little side of the jack determines the resistance at letoff

_________________________
Professional of the profession. Foo Foo specialistI wish to add some kind and sensitive phrase but nothing comes to mind.!

Yes, no sliding friction at the knuckle/jack interface would be ideal, but it's not the reality. I studied this effect quite closely using a Solidworks model of an action, and there's plenty of sliding. It is for this reason that people have experimented with rotating knuckles, and it is for this reason that Ron Overs changed the geometry of his action. I believe Ron's changes are both warranted and technically sound.

I don't think either Ron's action design or the Langer action on which it is patterned significantly reduce the friction between the tip of the jack and the knuckle. If you watch that interaction -- under actual playing conditions -- at very slow motion the tip of the jack tracks the knuckle fairly closely until the point of letoff. Then there is a lot of friction as it slides out from under the knuckle with some force.

I suppose what we really need is a combination of Ron's wippen with the articulated jack patented by Baldwin a few years back. (See US patent #6232537 B1 at <https://www.google.com/patents/US6232537?dq=piano+action+inassignee:Baldwin&ei=qvX3UfmGAcjmigKCpoC4AQ&cl=en>)

I suppose what we really need is a combination of Ron's wippen with the articulated jack patented by Baldwin a few years back. (See US patent #6232537 B1 at <https://www.google.com/patents/US6232537?dq=piano+action+inassignee:Baldwin&ei=qvX3UfmGAcjmigKCpoC4AQ&cl=en>)

ddf

A variant of the Hickman action--which I see they referenced under another name. Seems like the patent might be difficult to defend. . . .

Yes, no sliding friction at the knuckle/jack interface would be ideal, but it's not the reality. I studied this effect quite closely using a Solidworks model of an action, and there's plenty of sliding. It is for this reason that people have experimented with rotating knuckles, and it is for this reason that Ron Overs changed the geometry of his action. I believe Ron's changes are both warranted and technically sound.

I don't think either Ron's action design or the Langer action on which it is patterned significantly reduce the friction between the tip of the jack and the knuckle. If you watch that interaction -- under actual playing conditions -- at very slow motion the tip of the jack tracks the knuckle fairly closely until the point of letoff. Then there is a lot of friction as it slides out from under the knuckle with some force.

I suppose what we really need is a combination of Ron's wippen with the articulated jack patented by Baldwin a few years back. (See US patent #6232537 B1 at <https://www.google.com/patents/US6232537?dq=piano+action+inassignee:Baldwin&ei=qvX3UfmGAcjmigKCpoC4AQ&cl=en>)

ddf

This is an interesting topic. Although you are certainly correct that there's lots of relative motion at letoff, I've noticed that at anything but a pp key press, letoff is not very noticeable. I suspect, but have not attempted to verify, that this effect is caused by the fact that at letoff there is a reasonable amount of momentum in the key and wippen, and that momentum carries the action through letoff with little additionally force required by the pianist.

I tentatively believe that friction at the beginning of the key press is more noticeable, perhaps because there is no momentum there, and at the start of the key stroke static friction is noticeable. Excess friction seems to cause a breakaway feel instead of a smooth motion.

Yes, no sliding friction at the knuckle/jack interface would be ideal,

Not sure I agree with this. The added resistance at letoff gives the pianist critical information of when to "go for it". I have experimented with eliminating that perception of resistance at letoff, by both raising drop very very high and advancing the jack into the cheat zone. In both instances it became very difficult, from a pianistic stand point to gauge where I was in the keystroke and how much pressure I should apply to get the tone I wanted.

Steingraber experimented with and produced a rolling knuckle for a little while. Udo pulled it entirely because pianists hated it.

Jim Ialeggio

I'm not convinced that the cause of the common perception you mention is really understood. I can give some counter examples. I have played a piano with a Hickman action, which has very low friction in general, and no sliding parts. Letoff in a Hickman action is much smoother and less noticeable. I found it delightful, and it did not seem strange or difficult to control. We've all run into pianos whose knuckle/jack friction is too high, and those actions feel pretty terrible.

It may be that without jack/knuckle friction, the standard action misbehaves in some subtle way, and some additional change or adjustment to the action may correct the negative perception.

I think it's also possible that part of the issue is that people who have developed a high level of expertise at playing the piano have usually spent thousands of hours in front of keyboard. Almost any change in action feel outside of the normally encountered range of variations will feel foreign and not quite right. I suspect that some action improvements would take a few weeks of acclimation before their worth could be judged.

the energy that is stored during the first part of the hammer acceleration can be manipulated furthermore during the beginning of the letoff.

the resistance perceived is a tool for the pianist, if it is too light the management of the hammer acceleration is to be done from a higher position above the keybed because the perceptions are to be felt during the first part of the stroke.

A too heavy letoff is a hassle - a good even resistance at letoff allows the pianist to use the end of the key dip as his reference for touch, which is less tiring.

the pianists of the 50 's begun to talk of the way the tone can be produced from the bottom of the keyboard.Without an adequate resistance/control during letoff, this is not so much possible.

To resume, that is the friction that provide information to the amount of energy stored in the shank and action.

Without any friction it may be difficult to slow the key , as done at the last moment some time (I even believe some pianists can slow the acceleration just enough to take control and accelerate a little more during the last (extra fast, with higher leverage change than before) acceleration during the jack trip)

Edited by Olek (07/31/1309:20 AM)

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Professional of the profession. Foo Foo specialistI wish to add some kind and sensitive phrase but nothing comes to mind.!

I'm not convinced that the cause of the common perception you mention is really understood. I can give some counter examples.

yes...as usual the picture is not black and white.

One the one hand, in a modern Erard type action,in a well set up friendly let-off action, even if the friction of let-off is seemingly imperceptible at speed, why do pianists acutely sense the amount of aftertouch, and why do they scream when it differs as little as .005-.010"?

ON the other hand, I have also played Brown actions which have no aftertouch...they don't need it. They were really fun, easy actions to play...but the hammer weights are significantly less than even "light" modern hammer weights. Add more hammer weight and its accompanying inertia to these actions and they become monsters.

I really think the inertia question is what drives the pianistic requirements of what events need to be perceived during the stroke.

I'm not convinced that the cause of the common perception you mention is really understood. I can give some counter examples.

yes...as usual the picture is not black and white.

One the one hand, in a modern Erard type action,in a well set up friendly let-off action, even if the friction of let-off is seemingly imperceptible at speed, why do pianists acutely sense the amount of aftertouch, and why do they scream when it differs as little as .005-.010"?

ON the other hand, I have also played Brown actions which have no aftertouch...they don't need it. They were really fun, easy actions to play...but the hammer weights are significantly less than even "light" modern hammer weights. Add more hammer weight and its accompanying inertia to these actions and they become monsters.

I really think the inertia question is what drives the pianistic requirements of what events need to be perceived during the stroke.

Jim Ialeggio

Another interesting question. If the pianist is playing even somewhat loudly, he is accelerating the key hard enough to allow the action to go through escapement even if he doesn't explicitly push the key all the way down. If he is playing softly, and if the escapement is adjusted to be minimal, then he has to be careful lest some notes don't go through escapement. I suspect it is the latter condition that causes pianists to be picky about when escapement occurs. (Just a semi-educated guess)

I'm not convinced that the cause of the common perception you mention is really understood. I can give some counter examples.

yes...as usual the picture is not black and white.

One the one hand, in a modern Erard type action,in a well set up friendly let-off action, even if the friction of let-off is seemingly imperceptible at speed, why do pianists acutely sense the amount of aftertouch, and why do they scream when it differs as little as .005-.010"?

ON the other hand, I have also played Brown actions which have no aftertouch...they don't need it. They were really fun, easy actions to play...but the hammer weights are significantly less than even "light" modern hammer weights. Add more hammer weight and its accompanying inertia to these actions and they become monsters.

I really think the inertia question is what drives the pianistic requirements of what events need to be perceived during the stroke.

Jim Ialeggio

Another interesting question. If the pianist is playing even somewhat loudly, he is accelerating the key hard enough to allow the action to go through escapement even if he doesn't explicitly push the key all the way down. If he is playing softly, and if the escapement is adjusted to be minimal, then he has to be careful lest some notes don't go through escapement. I suspect it is the latter condition that causes pianists to be picky about when escapement occurs. (Just a semi-educated guess)

Hopefully there are more than a few ways to accelerate the key.

Pfeiffer when he tested with the free fall of a weight discovered that the loss of contact jack/knucke was very soon (about a little before mF)

So if the pianist wan to keep the control it have to use some tactile feedback and master the amount of weight he allow to go to the hand, then the hand manage the acceleration.

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Professional of the profession. Foo Foo specialistI wish to add some kind and sensitive phrase but nothing comes to mind.!